I had been glad to hear that you couldn’t hear Priuses as they passed by. I even stopped my engine once (I have a diesel) to hear the electric motor’s humming – it sounded differently than others, something I had never experienced before. That was in 2007.
Now, a decade after the Priuses first entered the Japanese market, all sorts of complaints coming from pedestrians arise, mostly from the blind. They just can’t hear the hybrids and don’t have the chance to get away from their path. If the driver’s not too careful, accidents can happen.
And they do, as the U.S. government’s auto safety agency found in a research that low-speed crashes involving pedestrians are two times more likely to happen, compared with those made by conventional engine powered cars.
For that matter, Toyota designed a $148 speaker system that should warn nearby pedestrians that a car is approaching. The noise level the device is going to produce is about the same with a regular engine.
The buzzer device is Toyota’s response to the society’s needs and was also requested three years ago, when I started writing about hybrid cars. It’s a good thing they kept the idea and further developed it.